Glazing panels

ABSTRACT

Glazing Panels suitable for vehicle windscreens comprise a solid coloured obscuration band ( 24 ) around the perimeter, a fade out band ( 26 ) extending inwardly therefrom and a multilayer transparent infra-red reflective and/or absorbing coating ( 28 ) have the outer edge of the coating positioned so as to lie within the fade out band ( 26 ). The panel reduces reflection caused by the transition between coated and uncoated areas of the glass. The panels may be laminates or bilayers.

DESCRIPTION

This invention relates to novel glazing panels.

Glazing panels, particularly vehicle glazings and particularlywindshields, are commonly secured in position using adhesive. Thesepanels may be flat or curved. The panels may be provided with an opaqueband extending around their entire periphery, the purpose of which is toimprove the appearance of the windshield by masking the interfacebetween the panel and the vehicle and to shield the adhesive fromultra-violet radiation which might damage its integrity over time. Thisopaque band, which is termed an obscuration band, generally comprises asolid coloured band extending around the periphery of the panel.Commonly the panels further comprise a fade out band extending inwardlyfrom the inner edge of the obscuration band in which the obscuration isapplied in a decorative pattern with anything from 1 to 99% of thesurface area of the glass being obscured. The fade out band improves thevisual appearance of the panel by avoiding a sharp transition betweenthe solid obscuration band and the clear glass.

Another common feature of the modern vehicle glazing panel is theprovision of a multilayer transparent infra-red reflective and/orabsorbing coating on the glass in which one or more layers reflect IRand/or solar radiation and thereby reduce the heat energy transmittedthrough the glazing. These coatings do not normally extend to the outeredge of the panel since they have a tendency to corrode if they do so.U.S. Pat. No. 5,492,750 describes a method of applying such a coating tothe surface of a glass which uses a mask to prevent deposition of thecoating around the periphery of the glass. The thickness of the mask issuch that it leaves a ghosting effect at the peripheral edge of thecoating which is stated to be undesirable because it highlights the edgeof the coating. Where the extremity of the coating does not overlap theobscuration band the changes in reflectance and transmittance betweenthe coated and the uncoated area of glass is noticeable and can distractthe driver's attention. Attempts to remove this distraction by ensuringoverlap between the solid portion of the obscuration band and the edgeof the coating have been discovered to be less than satisfactoryparticularly because when viewed from a position where the coating is inthe foreground and the obscuration band is in the background thetransition between the coated and non-coated areas of the glass is verynoticeable, and aesthetically displeasing. This is particularly truewhen a ghosting effect is present at the peripheral edge of the coating.EPA 0702 423 A1 discloses coated windscreens having a small area ofuncoated glass which transmits infra-red radiation. It is suggested thatthis uncoated area be covered with a layer for absorbing light in orderto give a more homogeneous appearance to the windshield.

We have now discovered that the appearance and the optical properties ofa glazing panel may be improved by providing that the edge of thecoating overlaps the fade out band but does not overlap with the solidportion of the obscuration band.

Thus from one aspect this invention provides a glazing panel having anobscuration band applied to at least one surface thereof any extendingaround the periphery of the panel, a fade out band extending inwardlytherefrom and at least one coating applied to at least one surfacethereof wherein the outer extremity of the coating lies within the fadeout band. Preferably the entire length of the edge of the coating willlie within the fade out band. However this may not always be possiblefor example due to the presence of rain sensors which are masked by asolid printed area. In such instances we prefer to position as much ofthe edge of the coating as is possible within the fade out band andgenerally to ensure that at least 90% of the edge of the coating lieswithin the fade out band.

The glazing panel may be a laminated panel or a bilayer panel. Laminatedpanels comprise two or more sheets of glass bonded together with asuitable resin which is typically polyvinylbutyral (PVB). Bilayer panelscomprise a single sheet of glass having a layer of transparent resinbonded to the interior surface. The invention finds particularapplication where the coating film is in the foreground (viewed from theinterior of the vehicle) and the obscuration band is in the backgroundalthough it is useful where the relative positioning of these two layersis reversed. In a laminated panel the obscuration band will not normallybe on the outer surface of the glass and is most commonly applied to theinnermost glass surface. The coating is most commonly applied to theunderside of the outermost panel of the laminate (often termed surface 2by application of the convention whereby the outermost surface is termedsurface 1 and the subsequent surfaces numbered consecutivelythereafter). In a bilayer panel the obscuration band and the coating arenormally applied to either the interior surface of the glass panel orthe interior face of the resin. The coating, the obscuration band andthe fade out band may be applied to a flat glazing panel, to a curvedglazing panel or to a flat glazing panel which is then curved.

In both laminates and bilayer panels the coating may be positioned inthe resin layer i.e. surrounded by resin and not being in contact withthe glass. These panels may be constructed by utilising a resin in whichthe coating is already positioned either to bond two glass sheetstogether or to bond to the underside of a single glass sheet. When thecoating is surrounded by the resin layer the coating may be depositedonto a transparent polymeric material (e.g. PET ) prior to theirincorporation in the laminate or bilayer. In this embodiment thepolymeric material incorporating the coating is preferably cut to theshape and size so that its extremities lie within the fade out band. Ina laminated panel the fade out band will normally be applied to asurface other than surface 1 of the laminate in this embodiment of theinvention.

The total width of the solid coloured section of the obscuration bandand the fade out band may vary through a wide range say from 5 mm to 300mm but is typically in the range 10 to 150 mm. The width of the solidobscuration band will be that which is sufficient to provide the desiredappearance The fade out band may be designed so as to have a decorativeeffect and the width and the shape of the band may be varied to providea particular appearance. The density of the shading within the fade outband may vary within wide limits with anything from 1 to 99% of thesurface area of the glass being covered with a solid cover. The densityof the colouration within the fade out band may vary across the width ofthe band e.g. by having a high percentage of the surface coloured in thearea adjacent to the solid coloured section of the obscuration band anda decreasing percentage of the surface coloured across the width of thefade out band or the density may remain constant across the fade outband.

The colouration in the fade out band may conveniently take the form of amultiplicity of dots of colour spread across the band. These dots may beof varying sizes (say from 0.001 to 10.00 mm) and varying shapes (forexample circular, rectangular, polygonal). The fade out band can alsotake the form of patterns other than dots for example lines of colour ofvarying widths running parallel to the obscuration band.

The outer edge of the coating typically a multilayer transparentinfra-red reflective coating will preferably overlap the edge of thefade out band by at least 0.1 mm and preferably at least 0.5 mm. Theedge will normally stop at least 0.1 mm and preferably at least 0.5 mmshort of the inner edge of the solid coloured obscuration band. Thecoating will preferably overlap the band along the entire periphery ofthat band.

A wide variety of reflective and/or absorbing coatings are used or havebeen proposed for use in the art. Any of these may be utilised in thepanels of this invention. These coatings may be of complex construction.One typical coating comprises a multilayer stack formed from successivelayers of metal oxide, silver, metal, metal oxide, silver, metal, metaloxide, metal oxide wherein the metal oxide is typically zinc oxide andthe metal is typically zinc.

The coatings may be applied to the glass using any of the knowntechniques e.g magnetron sputtering, e-beam evaporation, thermalevaporation, chemical vapour deposition and the like. Typically the areaon which the coating is deposited is controlled by masking the substrateor by deleting the coating from selected areas after it has beenapplied. As a result of some of the methods used the transition from thecoated to the uncoated area of the glass may not be sharp. There may bea transition zone at the edge of the coating area which may typically befrom 0.001 mm to 2.0 mm wide, depending upon the method used. Where theedge of the coating is defined by a mask this ghosting may be reduced oravoided by using a thinner mask, say one having a thickness less than200 microns and preferably less than 130 microns. From a secondembodiment the invention provides a method of forming a glazing panelhaving a reflective coating on at least one surface thereof, anobscuration band comprising a solid coloured section at the periphery ofthe panel and a fade out band extending inwardly therefrom on a surfacethereof which comprises applying the coating in a manner such that theouter extremity thereof lies within the fade out band.

Some illustrative embodiments of the invention will now be described byway of example by reference to the accompanying drawings in which:

FIGS. 1 to 9 inclusive are cross sectional views through laminatedglazing panels comprising two sheets of glass;

FIGS. 10 to 13 inclusive are cross sectional views through a bilayerglazing panel, and

FIG. 14 is a plan view of a glazing panel.

In each of the drawings the same numerals indicate the same or a similarpart.

In FIG. 1 the panel comprises an inner glass sheet 10 and an outer glasssheet 12 joined by a polyvinylbutyral (PVB) layer 14. The surfaces ofthe two sheets 10 and 12 are numbered Surface 1 to Surface 4 inclusivein accordance with the convention of the art. Obscuration band 16 isapplied to Surface 4. Fade Out Band 18 extends inwardly from theextremity of Band 16 on Surface 4. Coating 20 is applied to Surface 2.The extreme edge of coating 20 overlaps with the innermost edge of Band18.

FIG. 2 illustrates an alternative in which Obscuration Band 16 and FadeOut Band 18 are applied to Surface 3 of the panel. Coating 20 is appliedto Surface 2. The extremity of Coating 20 overlaps with the innermostedge of the Band 18.

FIG. 3 illustrates a second alternative in which Obscuration Band (16)and Fade Out Band (18) are applied to Surface 4 of the Panel. Coating 20is applied to Surface 3 of the Panel.

FIG. 4 illustrates another alternative in which Obscuration Band (16)and Fade Out Band (18) are applied to Surface 2 of the Panel and Coating20 is applied to Surface 3 of the Panel.

FIG. 5 illustrates another alternative in which Obscuration Band (16)and Fade Out Band (18) are applied to Surface 2 of the Panel and Coating20 is also applied to Surface 2 in a manner such that the outermost edgeof the coating overlaps with the innermost edge of Band 18.

FIG. 6 illustrates a further alternative in which Obscuration Band 16and Fade Out Band 18 are applied to Surface 3 of the Panel. Coating 20is also applied to Surface 3, again in such a manner that the outermostedge of Coating 20 overlaps with the innermost edge of Band 18.

FIG. 7 illustrates a further alternative in which the Obscuration Band(16) and the Fade Out Band (18) are applied to Surface 4 of the Panel.The Coating (20) lies within the PVB 14 between Surface 2 and Surface 3of the Panel.

FIG. 8 illustrates a further alternative in which the Obscuration Band16 and the Fade Out Band 18 are applied to Surface 3 of the Panel. TheCoating 20 again lies within the PVB 14 between Surface 2 and Surface 3of the Panel.

FIG. 9 illustrates a further alternative in which the Obscuration Band18 and the Fade Out Band 18 are applied to Surface 2 of the Panel.Coating 20 lies within the PVB 14 between Surface 2 and Surface 3 of thePanel.

FIG. 10 illustrates a bilayer panel which comprises an outer glass 12having a Bilayer Material 22 bonded to Surface 2 (the interior surfaceof outer glass 12). Obscuration Band 16 and Fade Out Band 18 are appliedto Surface 3 (the interior surface of Bilayer Material 22). Coating 20lies within the Bilayer Material 22. The outer extremity of Coating 22overlaps with the innermost edge of Fade Out Band 18.

FIG. 11 illustrates an alternative bilayer panel in which theObscuration Band 16 and the Fade Out Band are applied to Surface 2 ofthe Panel. Coating 20 is also applied to Surface 2 of the Panel and theoutermost extremity of Coating 20 overlaps Fade Out Band 18.

FIG. 12 illustrates an alternative bilayer panel in which theObscuration Band 16 and the Fade Out Band (18) are applied to Surface 2of the Panel. The coating 20 lies within the bilayer material 22.

FIG. 13 illustrates a further alternative for a bilayer panel in whichObscuration Band 16 and Fade Out Band 18 are applied to Surface 3 of thePanel. Coating 20 is applied to Surface 2 of the Panel.

FIG. 14 shows a plan view of a panel with a continuous solid band 24which represents the solid obscuration band 16. Dot Pattern 26represents the Fade Out Band 18. Line 28 Extent of Coating representsthe outermost extremity of the Coating 20. Non-Obscured Coated Area 30represents that portion of the coated area which extends beyond theinnermost edge of the Dot Pattern 26. Line 28 extends outwardly-beyondthe innermost edge of Dot Pattern 26 all round the periphery of DotPattern 26.

The embodiments of the invention may readily be produced using materialsand techniques which are known to the man skilled in the art. Care mustbe taken to ensure that the extremity of the coating extends beyond theinnermost edge of the Fade Out Band if necessary when the glazing panelis assembled from its component parts.

What is claimed is:
 1. A glazing panel comprising: (i) an obscuration band applied to at least one surface of the glazing panel and extending around the entire periphery of the panel, a fade out band extending inwardly from an inner edge of the obscuration band, and (ii) at least one reflective coating layer applied to at least one surface of the glazing panel, wherein the outer extremity of the coating layer lies within the fade out band.
 2. A panel according to claim 1 wherein the coating layer is in the foreground and the obscuration band is in the background.
 3. A panel according to claim 1 wherein the panel is a bilayer coated panel.
 4. A panel according to claim 3 wherein the coating and the obscuration band are applied to the inner face of the panel.
 5. A panel according to claim 1 wherein the panel is a laminated panel.
 6. A panel according to claim 5 wherein the obscuration band is applied to an interior surface of the laminate.
 7. A panel according to claim 5 wherein the coating is applied to an interior surface of the laminate.
 8. A panel according to claim 6 wherein the coating is applied to a surface of the glass closer to the outermost surface than the surface to which the obscuration band is applied.
 9. A panel according to claim 1 wherein the coating is applied to a transparent polymeric material which is incorporated into a laminated panel and the fade out band is on a surface other than the outermost surface of that laminate.
 10. A panel according to claim 1 wherein from 1 to 99% of the surface area of the fade out band is obscured.
 11. A panel according to claim 10 wherein the fade out band comprises a pattern of dots having an average size in the range 0.001 mm to 10 mm.
 12. A panel according to claim 1 wherein at least 90% of the edge of the coating layer lies within the fade out band.
 13. A panel according to claim 12 wherein the entire edge of the coating layer lies within the fade out band.
 14. A panel according to claim 1 wherein the outer edge of the coating overlaps the inner edge of the fade out band by at least 0.1 mm.
 15. A panel according to claim 1 where in the outer edge of the coating stops at least 0.1 mm short of the inner edge of the obscuration band.
 16. A method of forming a glazing panel having a reflective coating on at least one surface of the glazing panel and an obscuration band comprising a solid coloured section at its periphery and a fade out band extending inwardly from an inner edge of the obscuration band on a surface of the glazing panel, the method comprising applying said coating in a manner such that the outer extremity of the coating lies within the fade out band.
 17. A method according to claim 16 wherein the coating is applied by physical vapour deposition.
 18. A method according to claim 16 wherein the coating is applied to a polymeric transparent material and that polymeric transparent material is subsequently incorporated into a laminated panel.
 19. A method according to claim 16 wherein the panel is shaped after the coating has been applied. 